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RE: [css3-text] Adjacent and nested underlines (was Allow control of text-decoration width

From: Koji Ishii <kojiishi@gluesoft.co.jp>
Date: Sun, 10 Apr 2011 07:52:59 -0400
To: fantasai <fantasai.lists@inkedblade.net>
CC: "www-style@w3.org" <www-style@w3.org>
Message-ID: <A592E245B36A8949BDB0A302B375FB4E0AB3D55B64@MAILR001.mail.lan>
Ah...no, I still have one thing not understanding clearly.

> The position and thickness must be the same for
> a given text decoration application /per line box/.

Does inner application should have the same position/thickness as outer application when nested? To me, the inner application can either be part of parent's application or be its own application.

If so, the current spec guarantees to paint over, and Erick's hack/technique works in future too; i.e., "inherited" does what "reapply-*" needs to do.


Regards,
Koji

-----Original Message-----
From: www-style-request@w3.org [mailto:www-style-request@w3.org] On Behalf Of Koji Ishii
Sent: Sunday, April 10, 2011 5:49 PM
To: fantasai
Cc: www-style@w3.org
Subject: RE: [css3-text] Adjacent and nested underlines (was Allow control of text-decoration width

Thank you fantasai, it's much clearer now.

I'm worried Eric's hack[1] might stop working as browsers implement smarter thickness/position, because it becomes more likely that multiple underlines are not painted over for different font/size. Is drawing multiple underlines to the same text important? If not, could we change the semantics of such case to "keep the same position and thickness, but re-apply color and style"?

If it's difficult for backward compatibility or whatever other reasons, what do you think about adding "reapply-underline" value to the 'text-decoration-line' property just like we did "cancel-*" values? I guess implementing "reapply-*" is as much possible as "cancel-*" is.

I agree with Aryeh that changing color of part of an underline is not critical, but it's still a nice feature to have.

This doesn't resolve Aryeh's request to make his editor easier to implement, but at least it becomes implementable, while still making Chinese underlines happy.


Regards,
Koji

[1] http://lists.w3.org/Archives/Public/www-style/2011Apr/0254.html

-----Original Message-----
From: fantasai [mailto:fantasai.lists@inkedblade.net]
Sent: Sunday, April 10, 2011 10:26 AM
To: Koji Ishii
Cc: www-style@w3.org
Subject: Re: [css3-text] Adjacent and nested underlines (was Allow control of text-decoration width

On 04/09/2011 11:57 AM, Koji Ishii wrote:
>
> Here's a simplified version of Aryeh's example:
>
> .u { text-decoration: underline; }
> .r { color: Red; font-size:400%; }
>
> <p>Nested:<span class="u">a<span class="u r">b</span>c</span></p> 
> <p>Adjacent:<span class="u">d</span><span class="u r">e</span></p>
>
> The position and thickness must be the same throughout "each line", so 
> the question is what the "line" is. I think the spec doesn't state 
> this clearly, but I assume, a line starts by text-decoration-line:
> underline, overline, or line-through and ends at the end of the given 
> element. If an element is already part of a line, it will not start a new line.

"each line" is meant to refer to the line box, actually. The position and thickness must be the same for a given text decoration application /per line box/. So the position and thickness can be different if the element applying the text decoration splits across multiple lines. If multiple elements use text-decoration within the same line box, they can be different.

> If this is correct interpretation, the nested version has single line, 
> and the adjacent version has two lines. Can someone confirm this, or 
> correct me if my interpretation differs from yours?

End result of the interpretation is correct. :)

> Next about the color and style:
> ]]
> The color and line style of decorations must remain the same on all 
> decorations applied by a given element, even if descendant elements 
> have different color or line style values.
> [[
>
> This time, the spec says "by a given element", not "each line". I 
> understand this as color and style changes for "b" in the nested example. It also changes for "e"
> in the adjacent example as lines are split.

Yes. But note that the "b" in the nested example is underlined *twice*, once by the parent <span>, once by the child. For a solid underline, if the position of the underline does not change, the inner underline paints over the outer underline. But if the vertical-alignment of the span is changed, for example, you can see that there are two underlines applied to the "b".

> If all these interpretations are correct, I assume the expected results are:
> * The position and thickness are the same for "abc".
> * The position and thickness for "d" and "e" could be different.
> * Underlines for "b" and "e" are in red.

This is correct.

> I'd appreciate if someone can confirm/correct this. If correct, it 
> might be good to add the clarification of "what the line is" to the spec.

Agreed.

~fantasai
Received on Sunday, 10 April 2011 11:55:12 GMT

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